Effect of electric current heating on hot deformation resistance and microstructure of steels

The effect of electric current (EC) heating on the high temperature mechanical behavior and microstructure of plain carbon and austenitic stainless steels was examined using a Gleeble thermomechanical simulator. In stainless steel, EC heating is shown to reduce the flow stress, strain hardening rate, the apparent activation energy for deformation and to increase the strain rate sensitivity of the flow stress. These are accompanied by the acceleration of dynamic recrystallization and by an increase in recrystallized grain size. The EC effect is more pronounced at lower Zener-Hollomon parameters. In plain carbon steel, EC has almost no influence on flow stress. The EC heating effect on mechanical behavior and microstructure is related to deformation resistance, electric resistivity and heat conductivity of the material being tested.